> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.v2.rasen.ai/concepts/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.v2.rasen.ai/_mcp/server.

# API fundamentals

## Docs

- [Errors](https://docs.v2.rasen.ai/concepts/errors.md): One envelope, registered codes, and a retry class on every error.
- [Error codes](https://docs.v2.rasen.ai/concepts/error-codes.md): Every code this API returns, from the public error registry.
- [Idempotency and replay](https://docs.v2.rasen.ai/concepts/idempotency.md): Retry a mutation safely after a lost answer.
- [Revisions and ETags](https://docs.v2.rasen.ai/concepts/revisions.md): Edits name the version they change, so a stale edit never overwrites newer work.
- [Pagination](https://docs.v2.rasen.ai/concepts/pagination.md): Opaque cursors that last 24 hours.
- [Filters and limits](https://docs.v2.rasen.ai/concepts/filters.md): Repeated query parameters for everyday lists, a bounded POST for large ID sets.
- [Rate limits](https://docs.v2.rasen.ai/concepts/rate-limits.md): Per-key and per-workspace ceilings, reported on every response.
- [Resource keys](https://docs.v2.rasen.ai/concepts/resource-keys.md): Your own stable name for a piece of configuration.